1. Technical Field of the Invention
This invention relates to cellular telecommunications networks and, more particularly, to a combined home location register and service control point for providing enhanced subscriber services in a cellular telecommunications network.
2. Description of Related Art
In modern telecommunication systems, it has become increasingly important for network operators to be able to provide their subscribers with enhanced subscriber services. These services may include the provision of an 800 Services Database, a Credit Card Verification Database, Geographic Call Routing, Incoming Call Routing, Multi-location Extension Dialing, Network Automatic Call Distribution, Flexible Call Routing, Flexible Carrier Selection, CLASS Calling Name Delivery Database, and others. In wireline telephone systems, a method of providing such enhanced subscriber services is through an Advanced Intelligent Network (AIN).
FIG. 1 is a simplified block diagram of a typical wireline telecommunication system using the AIN to provide enhanced subscriber services. The AIN 12 and its associated Signaling System Number 7 (SS7) protocol are described in the industry standard, "TR-NWT-000246, Bell Communications Research Specification of Signaling System Number 7," which is incorporated by reference herein. A large number of Local Switches (LSs) 13a-n may be connected to a Service Switching Point/Tandem (SSP/T) 14 via multi-frequency (MF) links 15. A "tandem", as used herein, may be a local, LATA, or access tandem. The LSs 13a-n provide connections for subscribers 16a-n into the telecommunications system 11. The AIN 12 uses a system of high speed telecommunications links known as a Common Channel Signaling (CCS) network which employs the standard SS7 signaling protocol to link all of the components of the AIN 12. Standard telephony diagrams, and FIG. 1 herein, indicate links utilizing the SS7 signaling protocol as dotted lines and MF trunks as solid lines.
The components of the AIN 12 may include the SSP/T 14, one or more Signal Transfer Points (STPs) 18a-n which act as intermediate switching nodes, and one or more Service Control Points (SCPs) 19a-n. The SCPs 19 each contain a database of enhanced subscriber services which are accessed and controlled by a Service Logic Program (SLP). The SCP 19 currently utilizes a standardized AIN protocol built on the Transaction Capabilities Application Part (TCAP) for coordination of functions. The current version of the protocol required for communication with the SCP 19 is TCAP/AIN Release 0.1. The SCP 19 is described in the Bellcore recommendation, "TA-NWT-001280, Advanced Intelligent Network (AIN) Service Control Point (SCP) Generic Requirements," which is incorporated by reference herein. The SCP 19 acts as a repository for enhanced subscriber services which may be accessed by any one of the LSs 13a-n. In the absence of the SCP 19, each LS would have to be individually upgraded with enhanced subscriber services by distributing the service logic locally. With the implementation of the AIN 12, and the required communications capabilities in the LSs, new enhanced services need only be added to the SCP 19.
As seen from the above description, the AIN was developed strictly as a wireline communication system. The signaling protocol utilized for AIN allows only for control of telephone network switching elements in response to queries originated by network switching elements. The fixed nature of installed wirelines limits the utilization of the AIN. Therefore, following the development of the AIN, it was recognized that it would be beneficial for wireless communication systems to be able to access the AIN as well. Systems have been proposed that enable mobile telephone users to access the AIN for enhanced services.
One such system is described in U.S. Pat. No. 5,353,331 to Emery et al. (Emery). Emery discloses an integrated wired and wireless communications network that utilizes a SCP in an AIN to store enhanced subscriber services. A mobility controller (MC) is provided to enable access by mobile subscribers in a cellular telecommunications network. The cellular telecommunications network includes a home location register (HLR) which includes a database of subscriber information including location information and a subscriber profile. In Emery, the HLR and the SCP communicate via the TCAP-based communications protocol.
A major problem with systems such as Emery which integrate wireless communication systems with the existing wireline AIN is that they require that the TCAP-based AIN protocol be utilized for communication with the SCP and access to enhanced services. It is a very expensive and inefficient process for equipment suppliers in the cellular telecommunications industry to modify their equipment to utilize the AIN 0.1 protocol. There is no known solution to the above mentioned deficiency and shortcoming of existing systems for providing mobile subscribers with enhanced subscriber services.
It would be a distinct advantage to have a system which provides mobile subscribers with enhanced subscriber services and does not require access to the wireline AIN or modification of cellular equipment to utilize the TCAP-based AIN protocol. The present invention provides such a system.